The existing CDMA Interim Standard (IS-95 et seq.) was developed by the TIA (Telecommunications Industry Association) and EIA (Electronics Industry Association). In IS-95, when a transmission rate is utilized which is less than the full rate, a discontinuous (burst type) signal is transmitted. This signal is divided into logical frames which are 20 ms (milliseconds) in length. The frames are divided into 16 smaller portions (or slots) which are referred to as power control groups. The base station demodulator estimates the energy of each power control group received from the mobile station. If the energy is above a threshold (E.sub.s) then the base station will send back a power control signal directing the mobile to reduce its transmit power by one step. If the energy is below E.sub.s, then the power control signal will direct the mobile to increase its transmit power by one step. For full rate transmissions, each power control group is used and there is no problem.
The problems arise in the transmission rates that are not full rate, such as quarter rate. Presently, a quarter rate transmission will only transmit in a quarter, or four, of the power control groups. There will be nothing related to this transmission transmitted in the remaining twelve power control groups. However, the energy of the power control groups that are not used is still measured. This measurement results in the transmission of a power control signal from the base site to the mobile. Currently it is up to the mobile to keep track of which power control groups were used and to ignore power control commands that result from the energy measurement of power control groups that were not used.
The present systems use a bursted duty cycle (i.e. don't use all of the slots in a frame) for transmission of signals at rates other than full rate. Since there is only one threshold power level, in order to have an accurate reading, each burst must meet the same E.sub.s threshold as the continuous full rate transmission.